A while back we sold my wife's car - 2000 Legacy Outback - 2.5 and automatic 341,000 miles - to a local guy. He's trying to get it smogged and it failed it's first attempt. Gas limit at idle is 100ppm and the car was at 300. At 2500 RPM it was down to 166ppm but the limit is 130. He's a younger guy and not super versed in Subaru yet, so I offered to help as much as possible.

 

I have no prior experience in helping a vehicle get smogged. Hoping some of you would have some ideas on what to do/where to start. There's a twin to this car in a Pick N Pull close by so i've got some access to replacement parts if need be.

 

Thoughts and ideas on what can help it pass?

Which 'gas' is out of spec- one indicating too rich or incomplete combustion? Poorly operating converter?

 

Standard Q on age of plugs, wires, is PCV system operating properly, do the injectors leak down, has cleaning the injectors been tried (perhaps some of the serious stuff that connects in place of the fuel line),

 

You could always try the acetone trick, too...

clean/change the PCV valve ?

A couple months ago I had trouble getting a vehicle to pass emissions and I used the CRC "guaranteed to pass" stuff that is available at most auto parts stores. I also dumped in a couple bottles of Heet fuel line antifreeze, since I read that works well too. Not sure if all that was overkill, but I definitely passed that time!

HC is measured in PPM. Unburned hydrocarbons generally means either poor injection spray pattern, or poor ignition leading to incomplete burn of the fuel.

How old are plugs and wires?

Does it get fuel system cleaner on a regular basis?

I am the new person in question here. Thanks Adventure for passing this question onto the community. Clarifying these questions, it is the HC which read 300 ppm at idle, and 166 ppm at 2500 RPM. Additionally, the CO% is a bit high, 0.63 and 0.74%, respectively. This suggests there is incomplete burning of fuel, so Fairfax you may be right.

I have put Seafoam in the fuel line, in the crankcase, and also applied it to do "top end cleaning" as I've heard it called. The latter would seem to clean out the PCV valve, right? Either way a whole lot of gunk was vaporized out of the system when I did the last stage of Seafoaming, as shown by the huge clouds of crap spout from the exhaust.

In addition to this I will try adding acetone to premium gas to have it run cleaner before I take it in next time for smog.

Any other additions are most welcome.

Seafoam doesn't clean the PCV valve.

When poured into a vacuum line it cleans deposits from the intake manifold, the intake valves, and the combustion chamber and piston crown.

 

If the car hasn't had a full tune-up recently, spark plugs, wires, air filter, PCV valve, doing that can go a long way.

Good to see you made it on here!

 

Plugs and wires on the car are about new. Maybe 4000 miles. Air filter could stand to be replaced and PCV is the one that came on the car when we bought it about 100,000 miles ago.

Air filter could stand to be replaced and PCV is the one that came on the car when we bought it about 100,000 miles ago.

Then I would do those first. Use a Subaru PCV valve. The aftermarket cheapos can cause oil consumption problems.

Well great to hear these points, I just replaced the air filter and PCV valve. PCV valve was black as night. It wasn't a Subaru specific valve however, Fairfax so thanks for giving me a heads up, I'll monitor for that issue.